Development of an Analytical Method for Rear Differential Gear Whine Noise utilizing Principal Component Contribution by OTPA and CAE
Due to the global warming concern, CO2 emission regulations have been reinforced in most countries and electrification of automobiles has accelerated. Since the engine noise will be largely reduced, the improvements of gear whine noise becomes more important. But gear whine noise mechanism is complicated by involving many parts and transmitting paths to the cabin. Operational Transfer Path Analysis (OTPA) is one of the TPA methods to determine the main path and contributing part using only the operational data. However, in cases which many reference points are set on the same frame or body, the contribution becomes similar by high correlation among the reference data set and finding out the main transfer part becomes difficult. The contribution of principal component (PC) which is obtained from the correlated reference signals, instead of calculating the contribution from each reference point by modifying the OTPA process, has been utilized.